Propionamide (VS2H5CONH2), a complex alkylamide with twelve atoms, is the largest peptide-like molecule detected in space, according to a new study by Dr Juan Li from the Shanghai Astronomical Observatory and the Chinese Academy of Sciences.
“Proteins, as the building blocks of living cells, are an essential component of living systems on Earth,” wrote Dr Li and colleagues from China, Japan, France, Germany, United States and Ukraine in their article.
“Proteins are polymers of amino acids linked together by the peptide bond, -NHCO-.”
“Due to the high molecular weight and extremely low abundance of the gas phase, the detection of proteins in the interstellar medium at the current stage of development of observational facilities appears to be a formidable task.”
“Therefore, molecules with peptide-like bonds are of particular interest for our understanding of possible pathways of protein formation in space.”
In their study, astronomers focused on the giant molecular cloud complex Sagittarius B2 (Sgr B2).
“Sgr B2 is the region of massive star formation located near the galactic center, ”they wrote.
“It has proven to be one of the best hunting grounds for complex organic molecules in the interstellar medium.”
“Many prebiotic molecules have been detected in this source, such as the branched molecule iC3H7CN and the chiral molecule CH3CHCH2Oh. ”
“Sgr B2 contains two main star formation sites, Sgr B2 (N) and Sgr B2 (M), both of which host several dense, compact and hot nuclei.”
They analyzed the spectra of Sgr B2 obtained with the 30 m telescope of the Institute for Millimeter Radio Astronomy (IRAM) on Pica Veleta, Spain.
They also used archival interferometric data from the ReMoCA survey (Re-exploring Molecular Complexity with ALMA).
“Our results provide strong evidence for a hot, compact propionamide with high abundance in the hot nuclei of the Sgr B2 cloud complex,” the researchers wrote.
“From a chemical point of view, the presence of propionamide is not surprising. ”
“As a substituted acetamide and the third member of the amide chemical family, propionamide is likely to have formation mechanisms similar or associated with those of the two smaller amides: formamide and acetamide.”
“This detection suggests that large peptide-like molecules can form and survive during the star formation process and can form more complex molecules in the interstellar medium.”
Juan Li et al. 2021. Propionamide (C2H5CONH2): The largest peptide-like molecule in space. ApJ, in the press; arXiv: 2108.05001